U.S. patent number 5,901,488 [Application Number 09/001,688] was granted by the patent office on 1999-05-11 for piezoid electrical gun trigger.
This patent grant is currently assigned to AAI Corporation. Invention is credited to Richard P. Oberlin.
United States Patent |
5,901,488 |
Oberlin |
May 11, 1999 |
**Please see images for:
( Certificate of Correction ) ** |
Piezoid electrical gun trigger
Abstract
A method and apparatus for firing a firearm. A trigger is pulled
which causes a hammer to rotate away from an electrical power
source. After the hammer passes its maximum position, it is
released by the trigger releases it, thereby causing the hammer to
strike the electrical power source. The force from the hammer
causes electrical energy to flow from the electrical power source
to an electrically activated primer, thereby igniting the
primer.
Inventors: |
Oberlin; Richard P. (Phoenix,
MD) |
Assignee: |
AAI Corporation (Cockeysville,
MD)
|
Family
ID: |
21697327 |
Appl.
No.: |
09/001,688 |
Filed: |
December 13, 1997 |
Current U.S.
Class: |
42/84; 89/28.05;
89/28.1 |
Current CPC
Class: |
F41A
19/62 (20130101) |
Current International
Class: |
F41A
19/62 (20060101); F41A 19/00 (20060101); F41A
019/00 () |
Field of
Search: |
;42/84
;89/28.05,28.01 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Jordan; Charles T.
Assistant Examiner: Chelliah; Meeva
Attorney, Agent or Firm: Venable Baetjer Howard &
Civiletti, LLP
Claims
What is claimed is:
1. A gun trigger, comprising:
a piezoid;
a trigger;
a hammer positioned between said trigger and said piezoid; and
a primer which is electrically coupled to said piezoid, whereby
when said trigger is squeezed, it causes said trigger to engage
said hammer causing said hammer to first move away from said
piezoid and then, after said hammer passes its maximum position,
said trigger releases said hammer to strike said piezoid, thereby
causing electrical energy to flow from said piezoid to said primer,
thereby igniting said primer.
2. The gun trigger according to claim 1, wherein said hammer is
rotatably positioned between said trigger and said piezoid.
3. The gun trigger according to claim 2, wherein said piezoid is a
piezoid crystal having a first and a second terminal.
4. The gun trigger according to claim 2, wherein said primer is
electrically activated.
5. The gun trigger according to claim 4, wherein said electric
primer has a first contact, a second contact and an internal
resistance, whereby said electrical current generated by said
piezoid can flow through said internal resistance.
6. The gun trigger according to claim 5, wherein said first contact
is a primer contact and wherein said second contact is a barrel
contact which is connected to ground potential.
7. The gun trigger according to claim 5, wherein one of said
terminals of said piezoid is connected to one of said contacts of
said primer and the other of said terminals of said piezoid is
connected to the other contact of said primer.
8. The gun trigger according to claim 1, wherein said hammer is
rotatably positioned between said trigger and said piezoid.
9. The gun trigger according to claim 8 wherein said hammer further
comprises a hammer pivot around which said hammer rotates and said
trigger further comprises a trigger pivot around which said trigger
rotates.
10. The gun trigger according to claim 9, wherein said piezoid is a
piezoid crystal having a first and a second terminal.
11. The gun trigger according to claim 9, wherein said primer is
electrically activated.
12. The gun trigger according to claim 11, wherein said electric
primer has a first contact, a second contact and an internal
resistance, whereby said electrical current generated by said
piezoid can flow through said internal resistance.
13. The gun trigger according to claim 12, wherein said first
contact is a primer contact and wherein said second contact is a
barrel contact which is connected to ground potential.
14. The gun trigger according to claim 12, wherein one of said
terminals of said piezoid is connected to the first contact of said
primer and the other of said terminals of said piezoid is connected
to the second contact of said primer.
15. The gun trigger according to claim 6, wherein one of said
terminals of said piezoid is connected to one of said contacts of
said primer and the other of said terminals of said piezoid is
connected to the other contact of said primer.
16. The gun trigger according to claim 13, wherein one of said
terminals of said piezoid is connected to the first contact of said
primer and the other of said terminals of said piezoid is connected
to the second contact of said primer.
17. A gun trigger comprising:
a piezoid;
a frame;
a trigger;
a trigger spring connected between said trigger and said frame;
a trigger pull adjustment screw screwed into said frame, whereby
the tension in said trigger spring can be adjusted by rotating said
adjustment screw;
a hammer positioned between said trigger and said piezoid;
a hammer spring connected between said frame and said hammer;
a pawl rotatably connected to said trigger;
a pawl stop mounted to said trigger;
a pawl return spring connected between said pawl and said
trigger;
a trigger stop; and
a primer which is electrically coupled to said piezoid, whereby
when said trigger is squeezed, it causes said pawl to engage said
hammer causing said hammer to first rotate away from said piezoid
and then, after said hammer passes its maximum position, said pawl
clears said hammer thereby releasing said hammer causing said
hammer to strike said piezoid, thereby causing electrical energy to
flow from said piezoid to said primer, thereby igniting said
primer.
18. A method of firing a gun, comprising the steps of:
compressing an piezoid thereby generating a voltage; and
coupling said voltage to a primer, thereby igniting said
primer.
19. The method according to claim 18, wherein said coupling further
comprises inducing a current flow in said primer.
20. The method according to claim 18, wherein said compressing
further comprises striking said piezoid with a hammer.
21. The method according to claim 19, wherein said compressing
further comprises striking said piezoid with a hammer.
22. The method according to claim 20, wherein said compressing
further comprises rotating said hammer and then striking said
piezoid.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
This application is related to the following applications:
"One-Shot High-Output Piezoid Power Supply" by Richard P. Oberlin
and Robert T. Soranno; "Ultra Low-Power Fast Start Precision
Oscillator" by Richard P. Oberlin; "Muzzle Velocity Sensor" by
Richard P. Oberlin and Doug R. Cullison; "Accurate Ultra Low-Power
Fuze Electronics" by Richard P. Oberlin and Robert T. Soranno; and
"Self Correcting Inductive Fuze Setter" by Richard P. Oberlin and
Robert T. Soranno, each of which is filed concurrently herewith,
commonly owned, and incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to an improved firing mechanism for
firearms.
Previous methods for causing a projectile to be fired from a gun
included use of a percussion activated primer and a hammer. When
the hammer struck the primer, the primer fired, which in turn
ignited gunpowder in the projectile. As a result, the projectile
was propelled down the barrel and exited the gun.
In addition to mechanically firing a cartridge, previous methods
also involved electrically firing a cartridge by using a battery, a
switch and an electrically activated primer in the ammunition
instead of a conventional hammer/firing pin arrangement. In those
situations, the shooter pulled the trigger which acted upon the
switch to connect the battery to the detonator and thus to cause
the projectile to be fired. For example, U.S. Pat. No. 3,854,231
(Broyles) describes a small arms weapon in which the electrical
power for firing the gun is provided by a rechargeable storage
battery. In addition, provision is made, in the form of additional
circuitry, for recharging the battery.
Likewise, U.S. Pat. No. 5,625,972 (King) teaches the use of a gun
provided with an electronically fired cartridge. The cartridge or
projectile located in the gun includes a chamber with an explosive
and a primer cap with a heat activated primer. A fuse wire of
appropriate electrical resistance extends through the primer for
igniting the primer. It is connected in series with a switch and a
battery. When the switch is closed, the circuit is completed
causing electrical current to flow through the fuse wire. This
causes the wire to heat up, thereby igniting the primer.
However, there are many problems associated with the use of a
battery to supply the energy detonate the primer. First, the
battery has limited life and, therefore, has to be either replaced
or recharged periodically.
Second, the battery weighs a significant amount.
And third, batteries generate a low voltage (typically 9 volts) and
a good electrical contact has to be made to both the case and to
the primer electrode each time a new cartridge is loaded. As a
result, firing reliability is adversely affected by corrosion,
erosion, and a build-up of propellant residue as the gun ages and
as more rounds are fired between cleanings.
Piezoelectric elements have been used in weapon systems. For
example, U.S. Pat. No. No. 4,510,844 (Fritz) discloses a firing
mechanism for handguns which uses a piezo-voltage generator as one
of the sources of ignition energy. However, in order for the Fritz
ignition system to work, the breech block piece 22 must be
correctly positioned. Another difference between Fritz and the
disclosed invention is that the striking piece 5 in Fritz moves in
a linear, and not a circular path. Furthermore, although the Fritz
patent says that energy from the piezo generator is delivered to a
detonator, no detail is given as to how the detonator is
activated.
SUMMARY AND OBJECTS OF THE INVENTION
The present invention uses a hammer like device that is released by
the trigger and which strikes a piezoid (a piezo-electric ceramic)
that then generates a high voltage pulse that is applied to an
electrically sensitive primer, that is, a primer that requires
electrical energy for activation.
The main advantages are: (1) no battery is required that would have
to be replaced or recharged periodically; (2) a much higher voltage
is utilized which permits safer and more reliable operation because
the higher voltage can jump across gaps and can puncture through
thin non-conducting dirt films (additionally, a good low-resistance
electrical contact is not required); and, (3) when a hammer like
mechanism is added back into the weapon, it does not have to be
located with any specific relationship to the breech or barrel and
can be readily isolated from back blast and powder residue
accumulation.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a mechanical drawing of the trigger mechanism in the
rest/activate position;
FIG. 1B is a mechanical drawing of the firing mechanism in the
fully cocked position; and
FIG. 2 is an electrical schematic of the firing mechanism.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The operation of the piezoid electrical gun trigger according to
the present invention is as shown in FIGS. 1A and 1B and FIG.
2.
Trigger (m) and hammer (d) are normally returned to their rest
positions (as shown in FIG. 1A) by their respective springs; (j)
for the trigger and (b) for the hammer. Trigger (m) comes to rest
against trigger stop (l) and hammer (d) comes to rest against
piezoid (g) which is firmly anchored to weapon frame (a).
As the trigger (m) is squeezed (in the direction of the arrow
connected to trigger (m)), it rotates about trigger pivot (k). The
pull is adjustable by the combination of trigger pull adjustment
screw (f) and trigger spring (j). This action causes hammer (d) to
rotate about hammer pivot (c), thereby moving away from piezoid (g)
and stretching hammer spring (b), thus storing energy in the
spring.
As trigger (m) is continuously squeezed, hammer (d) reaches its
maximum position as shown in FIG. 1B. When the hammer (d) passes
this position, pawl (h) clears hammer (d), releasing the hammer
(d). Hammer (d) is then accelerated towards its rest position by
hammer spring (b) and strikes piezoid (g) while trigger (m)
continues to move until it is stopped by the edge of trigger stop
(l).
The resulting impact and rapid deceleration of hammer (d) by the
piezoid (g) causes piezoid (g) to compress slightly (a few
thousands of an inch). This causes piezoid (g) to generate a high
voltage (typically hundreds to thousands of volts). The voltage can
be tailored to any desired value by changing the piezoid layer
thickness. Generally several hundred volts would be utilized. Since
air has a nominal dielectric strength of 30 volts/mil, 600 volts
could jump a gap of 20 mils and/or breakdown a nonconducting film
of several mils. The total amount of energy available is
proportional to piezoid volume and decelerating pressure (10's of
thousands of ergs are readily generated).
The resulting voltage out of the piezoid is applied to an
electrically activated primer (n). This causes primer (n) to fire,
which in turn ignites propellant in projectile (p). As a result,
projectile (p) is propelled down the barrel and exits the gun. The
electrical path taken by the voltage is shown in FIG. 2. The
electrically stimulated primer (n) has a contact (o) which is
electrically connected to piezoid (g). The impact from the hammer
causes the piezoid to compress and generate hundreds to thousands
of volts causing electrical current to flow to the electrically
activated primer (n) in projectile (p) via contact (o), and then
exiting the primer (n) through gun barrel contact (q) which is
located on the projectile's (p) outer casing.
Finally, when trigger (m) is released, it is rotated towards the
rest position shown in FIG. 1A by trigger spring (j) until it is
stopped by trigger stop (l). During the trigger's return, pawl (h)
is deflected by hammer (d) which has returned to its rest position
after striking the piezoid (g). As the pawl (h) passes hammer (d)
during the trigger (m) return, it is released and the pawl return
spring (e) pushes the pawl (h) back to its rest position against
pawl stop (i).
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